The invention relates to a novel process for the manufacture of the compounds of formula I:
wherein R1-R5 are as defined in the detailed description and in the claims.
The pseudo proline dipeptides of formula I can be used as reversible protecting groups for Ser, Thr, and Cys and prove to be versatile tools for overcoming some intrinsic problems in the field of peptide chemistry [JACS 1996, 118, 9218-9227]. The presence of ΨPro within a peptide sequence results in the disruption of β-sheet structures considered as a source of intermolecular aggregation. The resulting increased salvation and coupling kinetics in peptide assembly such as Fmoc solid phase peptide synthesis facilitates chain elongation especially for peptides containing “difficult sequences”.